DESCRIPTION (provided by applicant: Modern microscopy methods have revolutionized cellular and sub-cellular imaging. Due to inherent high sensitivity and depth selectivity, confocal microscopy instruments deliver fluorescence and scattered light images of unprecedented resolution and contrast. Non-linear imaging techniques such as two photon excitation and second harmonic generation provide unique mechanisms of contrast for in situ measurements of superficial tissues. Additionally, intravital microscopy has transformed thin section microscopy to imaging of in vitro tissue cultures, in vivo microscopy of small animals and clinical human studies. Advancements in detection and signal processing have lead to intriguing new applications, for instance multi-dimensional microscopy such as multispectral detection and excitation coupled with fluorescence lifetime measurements. New features available in advanced microscopy systems have resulted from the development of rapidly tunable excitation lasers, sophisticated multi-channel detection systems and advanced photon counting electronics allowing time correlated single photon counting and fluorescence correlation spectroscopy. With this proposal we seek to obtain an advanced intravital microscope with a configuration that is optimized for intravital Imaging, nonlinear fluorescence and scattered light imaging, and fluorescence lifetime imaging. While our current shared user facilities are reasonably equipped, we have been stymied by restrictions that immobilize advanced microscopes into static turnkey configurations, restrict implementation of novel imaging protocols such as second harmonic and three photon imaging, due to the need to maintain vendor-defined system characteristics. Our proposed instrument is centered around a compromise of vendor integrated components and an open architecture system that will allow us to capitalize on our team's expertise in optical sciences, electronics and software design. Acquisition of this microscope will extend our extensive small animal imaging capabilities, from the existing macroscopic tissue level down to the cellular and molecular level. We will enable new avenues of our research such as quantifying fluorescence lifetime assessments to study bound versus unbound fluorophores or Foerster Energy Transfer efficiency in living tissues. Relevance: Microscopic imaging of cells and tissues is vastly evolving, on the one side with the discovery of new imaging techniques allowing deeper penetration and visualization of structures not seen before and on the other side by adapting the instruments to measure on living systems such as small animals and tissue culture systems. Many technological breakthroughs have been reported on highly specialized equipment and with this proposal we will translate advanced techniques into an instrument available for the University's research community in areas such as cancer research, infectious diseases, tissue regeneration and fundamental biological processes. [unreadable] [unreadable] [unreadable]